During manufacturing of a pneumatic tire, it is necessary to prepare a plurality of rubbery segments so as to build up them into a band by a band building machine. In order to prepare a plurality of rubbery segments, there have been proposed various types of cutting apparatus which are operative to cut an elongate non-vulcanized rubbery strip such as, for example, raw rubber into a plurality of segments on bias. Such oblique cutting surfaces of each segments contribute to increase in adhesion when both cutting surfaces are jointed to each other.
One of such cutting apparatus is known as "guillotine cutter" and largely comprises an anvil located immediately underneath the elongate non-vulcanized rubbery strip and a cutting plate upwardly spaced apart substantially in parallel from the anvil and extending obliquely to the transverse direction of the rubbery strip, the cutting plate being movable toward and away from the anvil so as to cut the rubbery strip on bias in cooperation with the anvil. The cutting plate is, namely, driven to move so as to be in contact with the rubbery strip throughout the length thereof and, then, pressed against the anvil through the thickness of the elongate rubbery strip for cutting off the rubbery segment from the elongate rubbery strip. A problem has been encountered in the prior-art cutting apparatus of above described nature in that a better surface finish can not be obtained due to viscoelasticity of the rubbery strip if the cutting plate is moved on a plane directed away from the upper surface of the rubbery strip at an angle less than about 45 degrees.
Another prior-art cutting apparatus for cutting the rubbery strip on bias is known as "ring cutter" and largely comprises a ring-shaped cutting tool driven for rotation by a suitable power source and transfer mechanism operative to move the cutting tool obliquely to the transverse direction of the rubbery strip. As the cutting tool produces a large amount of swarf, a problem has been encountered in another prior-art cutting apparatus of above described nature in that the swarf is attracted onto the rubbery strip. This results in deterioration in quality of the rubbery segments. Furthermore, another problem has been encountered in another prior-art cutting apparatus in that the rubbery strip is liable to twine about the cutting tool as a result of rotation thereof.
The present invention contemplates resolution of these problems inherent in the prior-art cutting apparatus of the nature.